Vacuum pump



S. BUKATA July 9, 1963 VACUUM PUMP Filed Dec. 22, 1960 3&9633? Patented July 9, 1963 free 3,096,928 VACUUM PUMP Stephen Bukata, 7813 Ardleigh St, Philadelphia 18, Pa. Filed Dec. 22, 1960, Set. No. 77,584 3 Claims. (Cl. 230-101) This invention relates to vacuum pumps, and more particularly, to a vapor diffusion pump.

A wide variety of vapor diflusion pumps have been proposed heretofore. Pumps of this type usually include a plurality of jet openings providing a plurality of jet stages in series. It is well known that as the pressure down stream of the jet increases, the pumping action of the jet gradually breaks down. The maximum pressure varies inversely with the width of the radial distance be.- tween the jet stages and the pump casing. The speed of the pump is directly proportional to the size of the jet stages. These design considerations present conflicting requirements requiring a compromise in the design of diffusion pumps.

Because of this compromise, most diffusion pumps known heretofore employ a plurality of jet stages spaced along the longitudinal axis of the pump. The size of the jet stages decreases progressively toward the vacuum side of the pump so that those stages near the inlet yield high pumping speed while those near the outlet afford good fore pressure tolerances. In many cases, this arrangement results in an extremely long pump which is difficult to handle and which occupies a large amount of space.

Since the pumps known heretofore are generally pro vided with stages one above the other, the pump must be tall enough to accommodate the jet system. As a general guide, the overall height of the pumps known heretofore is approximately four times the inlet diameter of the pump. The present invention overcomes the above and other disadvantages of diffusion pumps known heretofore.

It is an object of the present invention to provide a novel vacuum pump.

It is another object of the present invention to provide a novel vapor diffusion pump which is more compact and reduced in height than the pumps known heretofore.

It is another object of the present invention to provide a novel vapor diffusion pump which is more eflicient and requires less heat than pumps known heretofore.

It is still another object of the present invention to provide a novel vapor diffusion pump wherein a plurality of jet stages are positioned approximately in the same plane and approximately equidistant from the liquid providing the vapors for each stage.

It is a further object of the present invention to provide a novel in line vapor difiusion pump capable of being stacked directly over a booster pump.

It is a further object of the present invention to provide a novel vapor diffusion pump capable of providing fractional distillation.

Other objects will appear hereinafter.

For purposes of illustrating the invention there is shown in the drawings forms which are presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.

FIGURE 1 is a transverse schematic view of vapor pumps known heretofore and capable of being designated as the prior art.

FIGURE 2 is a transverse sectional view of a vacuum pump built in accordance with the principles of the present invention.

Referring to the drawing in detail, wherein like numerals indicate like elements, there is shown in FIGURE art. The stages are one above the other, consequently the pump must be tall enough to accommodate the jet system and has an overall heigth which is approximately four times the inlet diameter of the pump. The oil vapor rising to stage one will be cooled by the jet assembly because of the distance traveled. Consequently, there is a loss of vapor velocity and a decrease in pumping speed.

As shown more clearly in FIGURE 2, an in line vapor diffusion pump is shown designated generally as 60. The diffusion pump 60 is provided with a generally cylindrical housing 62 having an annular sump 64. A layer of oil is provided within the annular sump 64. The housing 62 is provided with an upper tapered wall 66 which merges into the inlet conduit 68.

An umbrella or interior wall 70 is disposed within the housing 62. The umbrella 70 is provided with peripheral portions disposed radially inwardly from the exterior wall of the housing 62. Cooling coils 72 are disposed on the lowermost surface of the umbrella 70 and on the inner surface of the depending flange portion on the periphery of the umbrella 70.

The inlet conduit 68 is provided at its lowermost end with a radially outwardly flared portion 74 within the housing 62. The lowermost edge of the flared portion 74 is disposed intermediate the top and bottom edges of a tapered disc 76 which surrounds the flared portion 74. The flared portion 74 cooperates with the tapered disc 76 to form the first jet stage.

The bottom edge of the tapered disc 76 is disposed intermediate the top and bottom edges of a tapered disc 78. The tapered disc 78 surrounds the tapered disc 76. The bottom edge 80 of the tapered disc 76 cooperates with the tapered disc 78 to form the second jet stage. The second jet stage is closer to the umbrella 70 than the first jet stage.

The outer periphery of the tapered disc 7 8 is provided with an inturned flange 82. An annular upright wall 84 is provided within the housing 62. The wall 84 extends upwardly from the annular sump 64 to a point just below the outer peripheral edge or" the tapered disc 78. The upper edge of the wall 84- is provided with an inturned flange 86. The flanges 82 and 86 cooperate to form the third jet stage. The third jet stage is closer to the umbrella 70 than the second jet stage. A wall 84 cooperates with the inner peripheral wall of the annular sump 64 to define an annular drain passage 88. For all practical purposes, the housing 62 is annular in shape with the umbrella 70 and its depending flange forming the major portion of the inner peripheral wall of the housing 62.

1 a diffusion pump which may be considered the prior The umbrella 70 cooperates with an annular tapered wall 90 having cooling coils 92 to form a cyclone separator 94. The cyclone separator 94 is provided with inlet passages 96 which are in communication with the third stage and enter the cyclone separator 94 tangentially. An outlet conduit 98 extends through the wall 90. The conduit 98 extends to a point adjacent the umbrella 70 and is in line with the inlet conduit 63. Thus, the gas entering through inlet 68 exists in the same direction through the outlet 98. Thus, it is possible to stack a diffuser pump directly over a booster pump and thereby provide a very compact installation.

When the gas enters the cyclone separator 94, it expands and consequently there is a loss in velocity. The cyclone separator efiiciently removes entrained oil vapor which would normally leave the pump through the outlet 98. The outer periphery of the wall 90 is lower than the inner periphery so that the entrained oil vapor removed from the gas by the cyclone separator discharges into the drain passage 88. In this manner, the cyclone separator 94 prevents a depletion of the oil in the oil sump 64.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification as indicating the scope of the invention.

1 claim:

1. A vapor pump comprising a housing having an oil sump, a layer of oil in said sump, means for heating said oil, a gas inlet conduit in communication with the interior of said housing, a gas outlet conduit in communication with-the interior of said housing at a point spaced from said inlet conduit, cooling means, an interior wall axially in line with said inlet and outlet conduits and spaced inwardly from the inside Wall of said housing, said cooling means being juxtaposed to said interior Wall, means defining at least two annular vapor jet stages in series between said inlet and outlet conduits, said stages being arranged to direct oil vapor against said interior wall so that said oil vapors condense on said interior wall, the jet stage closest to said layer of oil being spaced closer to said interior wall than the other stages, a vapor condensate drain below the lowermost stage, said drain being in communication with said sump, said jet stages surrounding said interior wall.

2. A vapor pump in accordance with claim 1 including substantially parallel discs, at least two annular vapor jet stages being defined by the space between overlapped edge portions of said substantially parallel discs, said discs being axially in line with said inlet and outlet conduits and said interior wall.

3. A vapor pump in accordance with claim 1 including a cyclone separator partially defined by said interior wall, said outlet conduit being in communication with said cyclone separator, the inlet to said cyclone separator being in communication with said jet stage closest to said layer of oil, and the inlet to said cyclone separator entering said cyclone separator tangentially thereof.

References Cited in the file of this patent UNITED STATES PATENTS 2,080,421 Hickman May 18, 1937 2,112,037 Malter Mar. 22, 1938 2,608,343 Col'aiaco Aug. 26, 1952 2,888,190 Denton May 26, 1959 2,905,373 Scatchard Sept. 22, 1959 

1. A VAPOR PUMP COMPRISING A HOUSING HAVING AN OIL SUMP, A LAYER OF OIL IN SAID SUMP, MEANS FOR HEATING SAID OIL, A GAS INLET CONDUIT IN COMMUNICATION WITH THE INTERIOR OF SAID HOUSING, A GAS OUTLET CONDUIT IN COMMUNICATION WITH THE INTERIOR OF SAID HOUSING AT A POINT SPACED FROM SAID INLET CONDUIT, COOLING MEANS, AN INTERIOR WALL AXIALLY IN LINE WITH SAID INLET AND OUTLET CONDUITS AND SPACED INWARDLY FROM THE INSIDE WALL OF SAID HOUSING, SAID COOLING MEANS BEING JUXTAPOSED TO SAID INTERIOR WALL, MEANS DEFINING AT LEAST TWO ANNULAR VAPOR JET STAGES IN SERIES BETWEEN SAID INLET AND OUTLET CONDUITS, SAID STAGES BEING ARRANGED TO DIRECT OIL VAPOR AGAINST SAID INTERIOR WALL SO THAT SAID OIL VAPORS CONDENSE ON SAID INTERIOR WALL, THE JET STAGE CLOSEST TO SAID LAYER OF OIL BEING SPACED CLOSER TO SAID INTERIOR WALL THAN THE OTHER STAGES, A VAPOR CONDENSATE DRAIN BELOW THE LOWERMOST STAGE, SAID DRAIN BEING IN COMMUNICATION WITH SAID SUMP, SAID JET STAGES SURROUNDING SAID INTERIOR WALL. 